Does anyone remember the experiment with a canister, long rubber tube, 1/2 cup baking flour, and a candle?
Use a metal canister with a friction fit lid, and do the experiment outdoors.
Poke a hole in the side of the canister toward the base, just large enough to fit the tube snugly, and insert the tube so it points downward. Place the flour in the canister, then the candle. Light the candle, press the lid in place, and blow hard through the tube.
When done right you get a nice flour dust explosion that can blow the lid up 100 feet or more, hence the need to do this outdoors.